import * as Cesium from "cesium";

// ImprovedNoise from Three.js
// https://github.com/mrdoob/three.js/blob/dev/examples/jsm/math/ImprovedNoise.js

const lerp = Cesium.Math.lerp;

const _p = [
  151, 160, 137, 91, 90, 15, 131, 13, 201, 95, 96, 53, 194, 233, 7, 225, 140,
  36, 103, 30, 69, 142, 8, 99, 37, 240, 21, 10, 23, 190, 6, 148, 247, 120, 234,
  75, 0, 26, 197, 62, 94, 252, 219, 203, 117, 35, 11, 32, 57, 177, 33, 88, 237,
  149, 56, 87, 174, 20, 125, 136, 171, 168, 68, 175, 74, 165, 71, 134, 139, 48,
  27, 166, 77, 146, 158, 231, 83, 111, 229, 122, 60, 211, 133, 230, 220, 105,
  92, 41, 55, 46, 245, 40, 244, 102, 143, 54, 65, 25, 63, 161, 1, 216, 80, 73,
  209, 76, 132, 187, 208, 89, 18, 169, 200, 196, 135, 130, 116, 188, 159, 86,
  164, 100, 109, 198, 173, 186, 3, 64, 52, 217, 226, 250, 124, 123, 5, 202, 38,
  147, 118, 126, 255, 82, 85, 212, 207, 206, 59, 227, 47, 16, 58, 17, 182, 189,
  28, 42, 223, 183, 170, 213, 119, 248, 152, 2, 44, 154, 163, 70, 221, 153, 101,
  155, 167, 43, 172, 9, 129, 22, 39, 253, 19, 98, 108, 110, 79, 113, 224, 232,
  178, 185, 112, 104, 218, 246, 97, 228, 251, 34, 242, 193, 238, 210, 144, 12,
  191, 179, 162, 241, 81, 51, 145, 235, 249, 14, 239, 107, 49, 192, 214, 31,
  181, 199, 106, 157, 184, 84, 204, 176, 115, 121, 50, 45, 127, 4, 150, 254,
  138, 236, 205, 93, 222, 114, 67, 29, 24, 72, 243, 141, 128, 195, 78, 66, 215,
  61, 156, 180,
];

for (let i = 0; i < 256; i++) {
  _p[256 + i] = _p[i];
}

function fade(t) {
  return t * t * t * (t * (t * 6 - 15) + 10);
}

function grad(hash, x, y, z) {
  const h = hash & 15;
  const u = h < 8 ? x : y,
    v = h < 4 ? y : h === 12 || h === 14 ? x : z;
  return ((h & 1) === 0 ? u : -u) + ((h & 2) === 0 ? v : -v);
}

/**
 * A utility class providing a 3D noise function.
 *
 * The code is based on [IMPROVED NOISE]{@link https://cs.nyu.edu/~perlin/noise/}
 * by Ken Perlin, 2002.
 *
 * @three_import import { ImprovedNoise } from 'three/addons/math/ImprovedNoise.js';
 */
class ImprovedNoise {
  /**
   * Returns a noise value for the given parameters.
   *
   * @param {number} x - The x coordinate.
   * @param {number} y - The y coordinate.
   * @param {number} z - The z coordinate.
   * @return {number} The noise value.
   */
  noise(x, y, z) {
    const floorX = Math.floor(x),
      floorY = Math.floor(y),
      floorZ = Math.floor(z);

    const X = floorX & 255,
      Y = floorY & 255,
      Z = floorZ & 255;

    x -= floorX;
    y -= floorY;
    z -= floorZ;

    const xMinus1 = x - 1,
      yMinus1 = y - 1,
      zMinus1 = z - 1;

    const u = fade(x),
      v = fade(y),
      w = fade(z);

    const A = _p[X] + Y,
      AA = _p[A] + Z,
      AB = _p[A + 1] + Z,
      B = _p[X + 1] + Y,
      BA = _p[B] + Z,
      BB = _p[B + 1] + Z;

    return lerp(
      lerp(
        lerp(grad(_p[AA], x, y, z), grad(_p[BA], xMinus1, y, z), u),
        lerp(grad(_p[AB], x, yMinus1, z), grad(_p[BB], xMinus1, yMinus1, z), u),
        v,
      ),
      lerp(
        lerp(
          grad(_p[AA + 1], x, y, zMinus1),
          grad(_p[BA + 1], xMinus1, y, zMinus1),
          u,
        ),
        lerp(
          grad(_p[AB + 1], x, yMinus1, zMinus1),
          grad(_p[BB + 1], xMinus1, yMinus1, zMinus1),
          u,
        ),
        v,
      ),
      w,
    );
  }
}

// End ImprovedNoise from Three.js

// GeometryPrimitive
const {
  Cartesian3,
  destroyObject,
  DrawCommand,
  VertexArray,
  GeometryPipeline,
  Matrix4,
} = Cesium;

/**
 * Custom Primitive for Geometry
 */
class GeometryPrimitive {
  /**
   *
   * @param {*} options
   * @param {*} options.modelMatrix
   * @param {*} options.vertexShaderSource
   * @param {*} options.fragmentShaderSource
   * @param {*} options.uniformMap
   * @param {*} options.renderState
   * @param {*} options.pass
   */
  constructor(geometry, options) {
    this.options = options;
    this.geometry = geometry;
  }

  /**
   *
   * @param {*} frameState
   */
  update(frameState) {
    if (Cesium.defined(this._drawCommand)) {
      frameState.commandList.push(this._drawCommand);
      return;
    }
    if (this.geometry.constructor.createGeometry) {
      this.geometry = this.geometry.constructor.createGeometry(this.geometry);
    }

    const context = frameState.context;

    const attributeLocations = GeometryPipeline.createAttributeLocations(
      this.geometry,
    );
    const vertexArray = VertexArray.fromGeometry({
      context: context,
      geometry: this.geometry,
      attributeLocations,
    });

    // calculate boundingSphere
    const boundingSphere = this.geometry.boundingSphere;
    boundingSphere.center = Matrix4.multiplyByPoint(
      this.options.modelMatrix,
      boundingSphere.center,
      new Cartesian3(),
    );
    boundingSphere.radius = 1000000;

    this._boundingSphereWC = [boundingSphere];

    const shaderProgram = Cesium.ShaderProgram.fromCache({
      context: context,
      attributeLocations,
      vertexShaderSource: this.options.vertexShaderSource,
      fragmentShaderSource: this.options.fragmentShaderSource,
    });

    this._drawCommand = new DrawCommand({
      owner: this,
      boundingVolume: boundingSphere,
      primitiveType: this.geometry.primitiveType,
      vertexArray: vertexArray,
      shaderProgram,
      ...this.options,
    });
  }

  destroy() {
    return destroyObject(this);
  }

  isDestroyed() {
    return false;
  }
}
// GeometryPrimitive end

function makeTexture3D(context) {
  const size = 100;
  const dataLength = size * size * size;
  const data = new Uint8Array(dataLength);
  let i = 0;
  const scale = 0.05;
  const perlin = new ImprovedNoise();
  let vector = new Cesium.Cartesian3();
  const halfSize = Cesium.Cartesian3.fromElements(
    size / 2,
    size / 2,
    size / 2,
    new Cesium.Cartesian3(),
  );

  for (let z = 0; z < size; z++) {
    for (let y = 0; y < size; y++) {
      for (let x = 0; x < size; x++) {
        vector = Cesium.Cartesian3.fromElements(x, y, z, vector);
        vector = Cesium.Cartesian3.subtract(vector, halfSize, vector);
        vector = Cesium.Cartesian3.divideByScalar(vector, size, vector);

        const d = 1.0 - Cesium.Cartesian3.magnitude(vector);
        const tv =
          (128 +
            128 *
              perlin.noise((x * scale) / 1.5, y * scale, (z * scale) / 1.5)) *
          d *
          d;

        data[i] = tv;
        i++;
      }
    }
  }

  return new Cesium.Texture3D({
    context: context,
    width: size,
    height: size,
    depth: size,
    flipY: false,
    pixelFormat: Cesium.PixelFormat.RED,
    pixelDatatype: Cesium.PixelDatatype.UNSIGNED_BYTE,
    source: {
      arrayBufferView: data,
      width: size,
      height: size,
      depth: size,
    },
    sampler: new Cesium.Sampler({
      minificationFilter: Cesium.TextureMinificationFilter.LINEAR,
      magnificationFilter: Cesium.TextureMagnificationFilter.LINEAR,
    }),
  });
}

const vertexShader = /* glsl */ `
      in vec3 position3DHigh;
      in vec3 position3DLow;
      in vec3 normal;
      in vec2 st;
      in float batchId;

      out vec3 vOrigin;
      out vec3 vDirection;
      out vec3 vPosition;

      vec4 translateRelativeToEye(vec3 high, vec3 low) {
          vec3 highDifference = high - czm_encodedCameraPositionMCHigh;
          if(length(highDifference) == 0.0f) {
              highDifference = vec3(0);
          }
          vec3 lowDifference = low - czm_encodedCameraPositionMCLow;
          return vec4(highDifference + lowDifference, 1.0f);
      }

      void main()
      {
          vec4 p = translateRelativeToEye(position3DHigh, position3DLow);

          vOrigin = czm_encodedCameraPositionMCHigh + czm_encodedCameraPositionMCLow;

          vec3 modelPosition = position3DHigh + position3DLow;
          vPosition = modelPosition;

          vDirection = modelPosition - vOrigin;

          gl_Position = czm_modelViewProjectionRelativeToEye * p;
      }`;

const fragmentShader = /* glsl */ `
      precision highp float;
      precision highp sampler3D;

      in vec3 vOrigin;
      in vec3 vDirection;

      // https://github.com/mrdoob/three.js/blob/dev/examples/webgl_volume_cloud.html
      uniform vec3 base;
      uniform sampler3D map;
			uniform float threshold;
			uniform float range;
			uniform float opacity;
			uniform float steps;
			uniform float frame;

			uint wang_hash(uint seed)
			{
					seed = (seed ^ 61u) ^ (seed >> 16u);
					seed *= 9u;
					seed = seed ^ (seed >> 4u);
					seed *= 0x27d4eb2du;
					seed = seed ^ (seed >> 15u);
					return seed;
			}

			float randomFloat(inout uint seed)
			{
					return float(wang_hash(seed)) / 4294967296.;
			}

			vec2 hitBox( vec3 orig, vec3 dir ) {
				const vec3 box_min = vec3( - 0.5 );
				const vec3 box_max = vec3( 0.5 );
				vec3 inv_dir = 1.0 / dir;
				vec3 tmin_tmp = ( box_min - orig ) * inv_dir;
				vec3 tmax_tmp = ( box_max - orig ) * inv_dir;
				vec3 tmin = min( tmin_tmp, tmax_tmp );
				vec3 tmax = max( tmin_tmp, tmax_tmp );
				float t0 = max( tmin.x, max( tmin.y, tmin.z ) );
				float t1 = min( tmax.x, min( tmax.y, tmax.z ) );
				return vec2( t0, t1 );
			}

		  float sample1( vec3 p ) {
		  	return texture( map, p ).r;
		  }

		  float shading( vec3 coord ) {
		  	float step = 0.01;
		  	return sample1( coord + vec3( - step ) ) - sample1( coord + vec3( step ) );
		  }

		  vec4 linearToSRGB( in vec4 value ) {
		  	return vec4( mix( pow( value.rgb, vec3( 0.41666 ) ) * 1.055 - vec3( 0.055 ), value.rgb * 12.92, vec3( lessThanEqual( value.rgb, vec3( 0.0031308 ) ) ) ), value.a );
		  }

      void main() {
					vec3 rayDir = normalize( vDirection );
					vec2 bounds = hitBox( vOrigin, rayDir );
					if ( bounds.x > bounds.y ) discard;
					bounds.x = max( bounds.x, 0.0 );
					vec3 p = vOrigin + bounds.x * rayDir;
					vec3 inc = 1.0 / abs( rayDir );
					float delta = min( inc.x, min( inc.y, inc.z ) );
					delta /= steps;

					// Nice little seed from
					// https://blog.demofox.org/2020/05/25/casual-shadertoy-path-tracing-1-basic-camera-diffuse-emissive/
					uint seed = uint( gl_FragCoord.x ) * uint( 1973 ) + uint( gl_FragCoord.y ) * uint( 9277 ) + uint( frame ) * uint( 26699 );
					vec3 size = vec3( textureSize( map, 0 ) );
					float randNum = randomFloat( seed ) * 2.0 - 1.0;
					p += rayDir * randNum * ( 1.0 / size );

					vec4 ac = vec4( base, 0.0 );
					for ( float t = bounds.x; t < bounds.y; t += delta ) {
						float d = sample1( p + 0.5 );
						d = smoothstep( threshold - range, threshold + range, d ) * opacity;
						float col = shading( p + 0.5 ) * 3.0 + ( ( p.x + p.y ) * 0.25 ) + 0.2;
						ac.rgb += ( 1.0 - ac.a ) * d * col;
						ac.a += ( 1.0 - ac.a ) * d;
						if ( ac.a >= 0.95 ) break;
						p += rayDir * delta;
					}
					vec4 color = linearToSRGB( ac );
          color = czm_gammaCorrect( color );
					if ( color.a == 0.0 ) discard;
          out_FragColor = color;
      }
      `;

const viewer = new Cesium.Viewer("cesiumContainer", {
  orderIndependentTranslucency: true,
});
const texture3D = makeTexture3D(viewer.scene.context);
texture3D.generateMipmap();

const boxSideLength = 1.0;
const zoomScale = 10000;
const centerPoint = Cesium.Cartesian3.fromDegrees(
  113,
  33,
  (boxSideLength / 0.5) * zoomScale,
);

const modelMatrix = Cesium.Transforms.eastNorthUpToFixedFrame(centerPoint);

const boxSize = new Cesium.Cartesian3(
  boxSideLength,
  boxSideLength,
  boxSideLength,
);

const renderState = Cesium.RenderState.fromCache({
  depthMask: false,
  blending: {
    enabled: true,
    color: {
      red: 0.0,
      green: 0.0,
      blue: 0.0,
      alpha: 0.0,
    },
  },
  depthTest: {
    enabled: true,
    func: Cesium.DepthFunction.LESS_OR_EQUAL,
  },
  cull: {
    enabled: true,
    face: Cesium.CullFace.FRONT,
  },
});

const zoomMat = Cesium.Matrix4.fromScale(
  new Cesium.Cartesian3(zoomScale, zoomScale, zoomScale),
  new Cesium.Matrix4(),
);

Cesium.Matrix4.multiply(modelMatrix, zoomMat, modelMatrix);

const halfBox = Cesium.Cartesian3.multiplyByScalar(
  boxSize,
  0.5,
  new Cesium.Cartesian3(),
);
const negHalfBox = Cesium.Cartesian3.negate(halfBox, new Cesium.Cartesian3());

const boxGeometry = new Cesium.BoxGeometry({
  minimum: negHalfBox,
  maximum: halfBox,
});

const uniforms = {
  base: new Cesium.Color(0.1912, 0.2542, 0.3515, 0),
  map: texture3D,
  opacity: 0.25,
  range: 0.1,
  steps: 100,
  frame: 0,
  threshold: 0.25,
};

window.uniforms = uniforms;

const cmdUniforms = {};
for (const key in uniforms) {
  if (key) {
    cmdUniforms[key] = function () {
      return uniforms[key];
    };
  }
}

const primitive = new GeometryPrimitive(boxGeometry, {
  uniformMap: cmdUniforms,
  vertexShaderSource: vertexShader,
  fragmentShaderSource: fragmentShader,
  renderState: renderState,
  modelMatrix,
  pass: Cesium.Pass.TRANSLUCENT,
});

viewer.scene.primitives.add(primitive);

const cameraState = {
  destination: centerPoint,
  orientation: {
    heading: 4.159717744111784,
    pitch: -0.4648127266675117,
    roll: boxSideLength * zoomScale * 2,
  },
  duration: 0,
};
// viewer.camera.flyTo(camState);
const hpr = new Cesium.HeadingPitchRange(
  cameraState.orientation.heading,
  cameraState.orientation.pitch,
  boxSideLength * zoomScale * 2,
);
viewer.camera.lookAt(cameraState.destination, hpr);

// create params control UI
function createSlider(
  toolbar,
  { labelText, min, max, step, defaultValue, callback },
) {
  const container = document.createElement("div");
  container.style.cssText = `
          display: flex;
          align-items: center;
          gap: 10px;
          margin-bottom: 8px;
        `;

  const label = document.createElement("label");
  label.textContent = labelText;
  label.style.cssText = `
          color: #ffffff;
          font-family: Arial, sans-serif;
          min-width: 60px;
          font-size: 14px;
        `;

  const slider = document.createElement("input");
  slider.type = "range";
  slider.min = min;
  slider.max = max;
  slider.step = step;
  slider.value = defaultValue;
  slider.style.cssText = `
          width: 100px;
          cursor: pointer;
        `;
  slider.addEventListener("input", (e) => callback(e.target.value));

  const valueDisplay = document.createElement("span");
  valueDisplay.textContent = defaultValue;
  valueDisplay.style.cssText = `
          color: #ffffff;
          font-family: monospace;
          width: 30px;
          text-align: right;
        `;
  slider.addEventListener("input", (e) => {
    valueDisplay.textContent = parseFloat(e.target.value).toFixed(2);
  });

  container.appendChild(label);
  container.appendChild(slider);
  container.appendChild(valueDisplay);
  toolbar.appendChild(container);

  return slider;
}

function createUi() {
  const toolbar = document.getElementById("toolbar");

  toolbar.style.cssText = `
          position: fixed;
          top: 10px;
          left: 10px;
          padding: 15px 20px 5px 20px;
          background: rgba(40, 40, 40, 0.85);
          border-radius: 12px;
          box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
          backdrop-filter: blur(5px);
          z-index: 1000;
        `;

  createSlider(toolbar, {
    labelText: "opacity",
    min: 0,
    max: 1,
    step: 0.01,
    defaultValue: uniforms.opacity,
    callback: (val) => {
      uniforms.opacity = parseFloat(val);
    },
  });

  createSlider(toolbar, {
    labelText: "range",
    min: 0,
    max: 1,
    step: 0.01,
    defaultValue: uniforms.range,
    callback: (val) => {
      uniforms.range = parseFloat(val);
    },
  });
  createSlider(toolbar, {
    labelText: "steps",
    min: 20,
    max: 200,
    step: 1,
    defaultValue: uniforms.steps,
    callback: (val) => {
      uniforms.steps = parseFloat(val);
    },
  });
  createSlider(toolbar, {
    labelText: "threshold",
    min: 0,
    max: 1,
    step: 0.01,
    defaultValue: uniforms.threshold,
    callback: (val) => {
      uniforms.threshold = parseFloat(val);
    },
  });
}

createUi();
